[Gmsh] comments about tutorial files

[Takuya OSHIMA]

Hi,

We are doing some detailed review of the tutorial files (t1.geo -
t9.geo that come with Gmsh 2.4.2) as a process of creating teaching
materials for our FE code that uses Gmsh as preprocessing front
end. In the process, at the stage of the review until t3.geo, we came
to have the following comments (we hope we are not nitpicking). What
do you think?

Thanks,
Takuya

[t1.geo]
Line 62 "specifying their orientation": it might be better if we have
  an explanation that this applies only for lines and surfaces, and
  have an example in one of the following physical entity definitions
  so that one can see how to specify the orientation.

[t2.geo]
Overall, one may hardly be able to follow the tutorial since there is
  little explanation about which entities Points 8, 12, 16, 7, Lines
  102-105, etc. are referring to (and which exact process generated
  the entities). If the entity numbers are to be obtained by saving
  unrolled geometry as explained at the bottom of t2.geo, the
  explanation might be better to come at the top of the file and to be
  clearly stated as such.
Lines 32-33 "a list": it might be better if it is clearly stated that
  the list is referring to tmp[] (obvious for programmers, but not for
  non-programmers).

[t3.geo]
Line 40 "news": the special meaning of the variable may be worth
  being mentioned.
Lines 76-77 "`Tools->Options->Save as defaults' button": there does
  not seem to be such a button on the GUI?

Takuya OSHIMA, Ph.D.
Faculty of Engineering, Niigata University
8050 Ikarashi-Ninocho, Nishi-ku, Niigata, 950-2181, JAPAN